The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to a passive cooling system for a turbomachine.
Turbomachines typically include a compressor operationally linked to a turbine. Turbomachines also include a combustor that receives fuel and air which is mixed and ignited to form a high energy fluid or hot gases. The hot gases are then directed into a hot gas path toward turbine buckets or blades. Energy from the hot gases imparts a rotational force to the turbine blades. During operation, a portion of the hot gases escapes from the hot gas path and flows over a cover portion of the blades. The hot gases typically impinge upon a front, top side of the cover portion. Continuous exposure to the hot gases leads to a significant reduction in blade tip creep life. As such, cooling tip portions of the blades will lead to a longer service life for the turbomachine. Currently there exist various cooling systems for lowering turbine blade temperatures. Conventional cooling systems pass a cooling flow internally though rotating airfoil portions of the blades. The cooling airflow either travels through the rotating airfoil portions and passes out from tip portions of the blades, or circulates back through the airfoil portions.